Method and apparatus for transferring data and making on-the-fly correction of errors

Abstract

A method and apparatus for transferring data in a disc apparatus are disclosed which perform on-the-fly correction. The disc apparatus includes a disc drive for transferring read data to a disc controller after a head has read the data from a storage disc. This disc controller transfers the data from the disc drive to a host device. The data transferring method reads data recorded on the storage disc in a CKD format in which one block is composed of a plurality of subblocks each having an error correction code. Errors in the data are detected by use of an error detection code on a subblock-unit; and after correcting the data of the error-detected subblock, the corrected data on the subblock-unit are transferred with the data of at least the previous subblock, at a speed higher than a reading speed. The data transferring apparatus includes a read circuit for reading data recorded in a CKD format on the storage disc, in which one block is composed of a plurality of subblocks each having an error correction code. An error detection circuit detects an error in the read data by use of the error detection code on the subblock-unit; and a transfer circuit corrects the data of the error-detected subblock, and transfers the corrected data on the subblock-unit and, at the same time, transfers the data of at least the subblock positioned previous to the disc controller at the speed higher than the reading speed.

What is claimed is: 
     
       1. A method of transferring data in a disc apparatus including a disc drive for transferring, after a head has read the data from a storage disc, the read data to a disc controller, the disc controller transferring the read data from the disc drive to a host device, said method comprising: a step of reading data from said storage disc, the data being recorded in a format on said storage disc and having one block composed of a plurality of subblocks each added with an error correction code;   a step of detecting an error in the data read from said storage disc by use of an error detection code on a subblock-unit; and   a step of transferring, after correcting the data of the error-detected subblock, the corrected data to said disc controller on the subblock-unit, said transferring step including a step of transferring the subblocks, exclusive of the last subblock of said block, to said disc controller at the reading speed; and   a step of transferring the data of the last subblock of said block to said disc controller at the speed higher than the reading speed.   
     
     
       2. A method of transferring data in a disc apparatus according to claim 1, wherein said detecting step is a step of writing the read data to a buffer memory at the reading speed and, at the same time, detecting the error of the subblock by use of the error detection code through an error correction circuit. 
     
     
       3. A method of transferring data in a disc apparatus according to claim 2, wherein said transferring step is a step of correcting, after reading the data of the subblock from said buffer memory at the speed higher than the reading speed, the data of the subblock by use of an error correction signal of said error correction circuit and transferring the corrected data. 
     
     
       4. An apparatus for transferring data in a disc apparatus including a disc drive for transferring, after a head has read the data from a storage disc, the read data to a disc controller, the disc controller transferring the read data from the disc drive to a host device, said apparatus comprising: a read circuit for reading data from said storage disc, the data being recorded in a format on said storage disc and having one block composed of a plurality of subblocks each added with an error correction code;   an error detection circuit for detecting an error in the read data by use of an error detection code on a subblock-unit; and   a data transfer circuit for transferring, after correcting the data of the error-detected subblock, the corrected data to said disc controller on the subblock-unit, said data transfer circuit transferring the subblocks, exclusive of the last subblock of said block to said disc controller at the reading speed, and transferring the data of the last subblock of said block to said disc controller at the speed higher than the reading speed.   
     
     
       5. An apparatus for transferring data in a disc apparatus according to claim 4, wherein said data transfer circuit further includes a buffer memory to which the read data is written at the reading speed and from which the data is read at the speed higher than the reading speed. 
     
     
       6. An apparatus for transferring data in a disc apparatus according to claim 5, wherein said data transfer circuit is a circuit for reading the data from said buffer memory at the speed higher than the reading speed, correcting the data by an error correction signal of said error correction circuit and thereafter transferring the data.